Drive mechanism for articulation of a surgical instrument

Abstract

A surgical instrument includes a housing, an end effector and an elongated shaft extending therebetween. The elongated shaft includes a distal portion that is movable between aligned and articulated configurations. A pair of drive cables extends through the elongated shaft and is coupled to the distal portion such that reciprocal longitudinal motion of the drive cables induces movement of the distal portion between the aligned and articulated configurations. An articulation drive mechanism is operable to induce reciprocal longitudinal motion of the drive cables. The drive mechanism includes an actuator and a pair of torsion members that are rotatable about two distinct axes in response to movement of the actuator. A respective follower is operatively coupled to each torsion member to translate in a respective longitudinal direction in response to rotation of the torsion members, and each follower is coupled to a respective drive cable to impart translational motion thereto.

What is claimed is: 
     
       1. A surgical instrument, comprising:
 a housing; 
 an end effector; 
 an elongated shaft extending between the housing and the end effector, at least a portion of the elongated shaft defining an articulation section for articulating the end effector relative to the housing; 
 first and second drive cables extending at least partially through the elongated shaft and coupled to the articulation section, the first and second drive cables configured for longitudinal movement in opposite directions to articulate the end effector relative to the housing; and 
 an articulation drive mechanism including an actuator and first and second torsion members operably coupling the actuator to the first and second drive cables, respectively, wherein the actuator is selectively actuatable for simultaneously rotating the first and second torsion members in opposite directions to longitudinally move the first and second drive cables in opposite directions, thereby articulating the end effector relative to the housing, wherein the actuator includes a rotatable articulation wheel and wherein the first and second torsion members are coupled to the rotatable articulation wheel on opposing sides thereof, the rotatable articulation wheel including a plurality of teeth disposed on each lateral side thereof, and wherein each torsion member includes threading configured to engage the corresponding plurality of teeth of the rotatable articulation wheel. 
 
     
     
       2. The surgical instrument according to  claim 1 , wherein the first and second torsion members are coupled to the first and second drive cables, respectively, via first and second followers such that rotation of the first and second torsion members in opposite directions effects respective longitudinal translation of the first and second followers in opposite directions. 
     
     
       3. The surgical instrument according to  claim 1 , wherein the threadings of the first and second torsion members are pitched in the same direction. 
     
     
       4. The surgical instrument according to  claim 1 , wherein rotation of the rotatable articulation wheel in a first direction rotates the first and second torsion members inwardly towards the rotatable articulation wheel. 
     
     
       5. The surgical instrument according to  claim 1 , wherein rotation of the rotatable articulation wheel in a second direction rotates the first and second torsion members outwardly away from the rotatable articulation wheel. 
     
     
       6. The surgical instrument according to  claim 1 , wherein the rotatable articulation wheel is rotatable in a vertical plane aligned with a longitudinal axis of the elongated shaft. 
     
     
       7. The surgical instrument according to  claim 1 , wherein the end effector includes a pair of jaw members, and wherein at least one of the jaw members is movable relative to the other between an open position and a closed position for grasping tissue therebetween. 
     
     
       8. The surgical instrument according to  claim 7 , wherein at least one of the pair of jaw members is coupled to a source of electrical energy. 
     
     
       9. An articulation mechanism configured for use with a surgical instrument, comprising:
 an articulating portion including a plurality of articulation links interconnected by at least one articulation joint; 
 first and second drive cables coupled to the articulating portion at the distal ends thereof, the first and second drive cables configured for longitudinal movement in opposite directions to articulate the plurality of articulation links relative to one another; 
 first and second torsion members coupled to the proximal ends of the first and second drive cables, respectively; and 
 an actuator coupled to the first and second torsion members, the actuator selectively actuatable for simultaneously rotating the first and second torsion members in opposite directions to longitudinally move the first and second drive cables in opposite directions, thereby articulating the plurality of articulation links relative to one another, wherein the actuator includes a rotatable articulation wheel and wherein the first and second torsion members are coupled to the rotatable articulation wheel on opposing sides thereof, the rotatable articulation wheel including a plurality of teeth disposed on each lateral side thereof, and wherein each torsion member includes threading configured to engage the corresponding plurality of teeth of the rotatable articulation wheel. 
 
     
     
       10. The articulation mechanism according to  claim 9 , wherein the first and second torsion members are coupled to the first and second drive cables, respectively, via first and second followers such that rotation of the first and second torsion members in opposite directions effects respective longitudinal translation of the first and second followers in opposite directions. 
     
     
       11. The articulation mechanism according to  claim 9 , wherein the threadings of the first and second torsion members are pitched in the same direction. 
     
     
       12. The articulation mechanism according to  claim 9 , wherein rotation of the rotatable articulation wheel in a first direction rotates the first and second torsion members inwardly towards the rotatable articulation wheel. 
     
     
       13. The articulation mechanism according to  claim 9 , wherein rotation of the rotatable articulation wheel in a second direction rotates the first and second torsion members outwardly away from the rotatable articulation wheel. 
     
     
       14. The articulation mechanism according to  claim 9 , wherein the rotatable articulation wheel is rotatable about a rotation axis perpendicular to a rotation axis of the first and second torsion members. 
     
     
       15. An articulation mechanism for use with a surgical instrument, comprising:
 an articulation section including a plurality of articulatable links; 
 first and second drive cables coupled to the articulation section at the distal ends thereof, the first and second drive cables configured for longitudinal movement in opposite directions to articulate the articulatable links; 
 a rotatable articulation wheel including a plurality of teeth disposed on either lateral side thereof; 
 first and second torsion members coupled to the first and second drive cables at the proximal ends thereof, respectively, and disposed on either side of the rotatable articulation wheel, each torsion member defining threading configured to engage the corresponding plurality of teeth of the rotatable articulation wheel, the threading of each torsion member pitched in the same direction such that rotation of the rotatable articulation wheel rotates the first and second torsion members in opposite directions to longitudinally move the first and second drive cables in opposite directions, thereby articulating the articulatable links. 
 
     
     
       16. An articulation mechanism configured for use with a surgical instrument, comprising:
 an articulating portion including a plurality of articulation links interconnected by at least one articulation joint; 
 first and second drive cables coupled to the articulating portion at the distal ends thereof, the first and second drive cables configured for longitudinal movement in opposite directions to articulate the plurality of articulation links relative to one another; 
 first and second torsion members coupled to the proximal ends of the first and second drive cables, respectively; and 
 an actuator coupled to the first and second torsion members, the actuator selectively actuatable for simultaneously rotating the first and second torsion members in opposite directions to longitudinally move the first and second drive cables in opposite directions, thereby articulating the plurality of articulation links relative to one another, wherein the actuator includes a rotatable articulation wheel and wherein the first and second torsion members are coupled to the rotatable articulation wheel on opposing sides thereof, the rotatable articulation wheel being rotatable about a rotation axis perpendicular to a rotation axis of the first and second torsion members.